With the rapid development of image technology, camera modules are not only employed in consumer electronic devices, such as mobile phones, tablets, and notebooks, but also in machine vision and medical applications such as capsule endoscope. Among others, large field-of-view (FOV) camera modules are especially needed in a variety of applications including machine vision and capsule endoscope.
Machine vision typically requires a large FOV to detect and analyze the environment. A capsule endoscope is a diagnostic instrument in the form of a swallowable optical imaging device. The instrument is sized to be small enough to be swallowed by the patient. The capsule endoscope is typically provided with a wide-angle imaging lens system and an image sensor for receiving raw image data. It is very important that the endoscope be outfitted with high-quality, wide-angle, large-field-of-view optics to increase the possibility of obtaining desirable images.
Most conventional wide-angle lens systems include a number of lenses for incorporating into a lens system. Conventional lens systems typically employ molding glass or plastic lenses. However the cost of molded lenses is relatively high since molded glass or plastic lenses cannot be mass produced. Unlike traditional molded lenses, wafer-level lenses are produced by replicating a number of lenses on a wafer at the same time. Thus, it may lower the cost. Additionally, it can produce a small size wafer-level lens for compact camera module. Accordingly, wide-angle lens systems comprising wafer-level lenses for large FOV compact camera modules are demanded.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention.